Overview of Congenital Heart Disease Flashcards
Congenital Heart Disease
- heart defect of formation or function present at birth
- incidence: 8/1000 live births
- second most common congenital defect to neurological
Genetic Causes of CHD
- trisomy 21
- monosomies
- microdeletions
- single gene defects
- ~16% of CHD’s
Environmental Causes of CHD
- alcohol consumption
- ix’s (eg. rubella)
- drugs (eg. retinoic acid)
- maternal diseases (eg. diabetes - insulin is an important growth factor for myocardium, lupus - baby is born with a very low heart rate)
- 2% of CHD’s
Period when heart is starts forming
Weeks 4-8
When does heartbeat start?
Day 28
When are cardiac structures complete?
Weeks 7-8
When are genetic and environmental factors most important?
Weeks 4-8
Pathogenesis of the heart
-Due to an “injuring agent” that acts during a critical period to produce the abnormal development
Simple Lesion
-one defect in heart, eg. patent ductus arteriosus
Complex Defects
-multiple defects present, can sometimes make up a disease (eg. tetralogy of Fallot)
Most common defect
Bicuspid aortic valve - 1%
VSD
~32% of all CHD’s
Which CHD’s make up ~8% of all CHD’s each?
- ASD
- PDA
- Pulmonary Stenosis
- Aortic Stenosis
- Tetralogy of Fallot
Situs Inversus
-inversion of all organs in body
Isomerism
-having two of the same. e.g. two LV’s
Heterotaxy
-organs are distributed abnormally within body cavity
Heart Failure
-clinical syndrome characterized by symptoms resulting from heart disease
LV Failure
-when LV dysfunction results in fluid retention or exercise intolerance
LV Dysfunction
-abnormality of contraction (systole) or relaxation (diastole)
Pressure Equation
Pressure = Flow x Resistance
Congestive Heart Failure
-produces fluid retention in soft tissues
Heart Disease Symptoms
CHF can produce:
- dyspnea (alveolar edema)
- swelling in face/legs
- diaphoresis / fainting
- bloating in abdomen (ascites)
- poor feeding in young
- impaired exercise tolerance
Heart Disease Signs
- fetus: hydrops (fetal fluid retention), stillbirth, growth retardation
- newborn: respiratory distress, poor feeding, cyanosis with R->L shunts
- adults: murmurs, cardiac enlargement, sudden death
Two Types of CHF
- too much pulmonary blood flow
- reduced systemic flow
Structural Defects that can produce too much pulmonary blood flow CHF
- patent ductus arteriosus
- atrioventricular septal defect
- VSD’s
Structural Defect that can produce reduced systemic flow CHF
-obstructive left heart lesions
Non-Structural Causes of CHF
- myocardial failure
- circulatory volume overload (eg. anemia)
- respiratory disease (severe)
Cyanosis
- blue tinge to skin
- oxygen saturation 5 gm/L
- usually due to R->L shunts or lung disease
Cyanotic Lesions
- TOF
- Total anomalous pulmonary venous return
- Transposition of the great arteries
- Tricuspid valve abnormalities
- Pulmonary atresia
Investigation for Heart Disease
- Physical Exam/History
- Lab Values (CBC/Renal/Electrolytes)
- ECG
- Echo
- Radiography
- Catheter Hemodynamics
History
- younger patients, focus on pregnancy, family history of CHD
- feeding/growth
- activity
- color
- breathing
- sleeping patterns
- fainting spells
- palpitations
- chest pain (rarely seen)
- exercise tolerance
Physical Exam
- vitals including BP in four limbs
- work of breathing
- liver, lungs, soft tissue (congestion)
- cardiac activity/rhythm
- murmur timing and quality
- clubbing/cyanosis
Indications for Fetal Electrocardiography
- abnormal 4 chamber view on outside scan
- family history
- significant exposure to alcohol/drugs
- positive amniocentesis for chromosomal abnormality
- other evidence of syndrome
When are most CHD’s identified?
- at birth or shortly thereafter
- specific diagnosis made by more targeted investigations
Prognosis of CHD
-most can be treated if not cured
